High-potential electrical system



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M. MORRISON HIGH POTENTIAL ELECTRICAL SYSTEM 2 Sheets-Sheet 2 Filed July 23, 1920 vliwezzr QJrd i 071215022, L@ l MZ, w/,

Patented Oct. 19, 1926.

UNITED STATES PATENT OFFICE.

MONTEORD MORRISON, vor OAK rARiI, ILLINOIS, AssIGN'OR, RY illnsNE AssIoNMRNT-s, To VICTOR X-RAY CORPORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF NEW YORK.

HIGH-POTENTIAL ELECTRICAL SYSTEM Application mea :hay 23, 1920. serial No. 398,536.

My invention relates to electrical systems employing high potential current of such strength that dangerous, or deadly, results occur to living objects approaching close to,

or coming in Contact with, the electric-current-conducting elements traversed by. the high potential current, or inanimate ObJects positioned relatively closely to the apparatus may cause short circuits to be produced;

present day X-ray apparatus commonly 1nvolving such a system, wherein the current for operating the X-ray tubes is often maintained as high as 100,000 volts; my inventlon having been devised for embodiment more particularly in such apparatus, though not to the exclusion of its use in apparatus for other purposes.

Particularly in X-ray apparatus it is unavoidable, owing to the conditions presented,

that certain of the elements traversed `by .the high Otential current, be so exposed that there 1s danger of the patient Or operator, approaching so closelv to such elements as to receive an electric discharge of such intensity as to severely shock, and sometimes fatally, the patient or operator, as the case may be, and a fatal result is almost vcer'tam to occur should the patient, or operator, come in contact with such elements. y

My primary object is to rovide in a'high potential system wherein t e results abovereferred-to are possible, for the preventing of the'shocking of a living object, at least to a degree which would be injurious, should such ob'ect approach the elements traversed by the liifrh potential current andthe production o? undesirable short-circuits in the apparatuslin `the event of the movement of an inanimate Object into close proximity thereto. c y

vGenerally stated, my invention consists in providing means which will automatipally operate, should an object which would disturb the electric field, approach the elements carrying the high potential current to within a distance thereof beyond which, should the object approach such elements, the electric discharge taken by such object wouldbe of undesired intensity, to cause the How of such high potential current to be arrested, and preferably by breaking the low tension circuit from which the high potential current is derived.

Referring to the accompanying draw- 1n s:-` i 55 igures 1 2, 3 and 4 show, by views in the naturevof diagrams, the application of my invention to a plurality of X-ray systems, the embodiments shown being by way' of illustration only, the invention being applicable l'to other systems the use in connection with which, it is my purpose to claim my invention as well as those illustrated.

Referring to Fig. 1; 10 represents a rectifier, which may be ofan suitable construction and adapted to supp y direct current to an Xfray tube represented at 11 and which may be of any-suitable construction.

l The rectifier shown is provided with the four conta-cts 12, 13, 14 and 15 which are 70 represented as stationary and with which cooperate the current-conducting arcs 16 and 17 carried by a rotating disk 18 driven through the medium of a shaft 19 from a motor 20 which is driven at such speed, as is 75 well understood in the art, as to Cause the alternating-current delivered to the contacts 14 and 15 as hereinafter described, tO have uni-directional flow through the tube 1l,l the current being delivered to said tube through S0 the medium of wires 21 and 22 connected respectively with the terminals of the tube and with the contacts 13 and 12.

The `current from which the tube-operating direct current is supplied, is supplied through the wires 23 and 24 which lead to any suitable source of supply as for exam le an alternating current sup ly of 220 vo ts, the wires 23 and 24 connecting with the ends of the primary 25 of a high tension trans- D0 former 26, the secondary of whi'chis represented at 27 and the heavy insulation between the primary and secondary at 28, this being shown diagrammatically. The secondary 27 is connected atvits ends with the con- 95 tacts 14 and 15 as through the'medium of vthe wires 29 andBO, the transformer 26 being of such construction as to step-up the current to the desired high potential for the work to be performed.

The motor 20 is shown as supplied with current from the-line wires 23 and 24 arranged in arallel with the transformer 26, the wires or conducting current to the motor being represented at 31 and 32 and con- 105 nected with the wires 23 and 24 respectively.

The main line wire 24 is shown as having interposed therein switches 33 and 33a of any suitable type, the switch 33 being one which is required to be thrown by hand to a position for closing the circuit through the primary 25, and maintained in circuit-closing condition by the action of a magnetic coil 34, the switch 33 moving to open condition when the coil 34 is deenergized.

In accordance with the illustrated embodiment ot' my invention, I provide an electrostatic relay represented at 35 and shown as comprising a pair of disks 36 and 37 supported from a base 38 and out of electrical contact with each other, one of these disks being supported from the upright 39 and the other rom a depending arm 40 pivoted to the upper end of an upright 41, there bcing provided, to extend into the space between the disks 36 and 37 and out of contact therewith, a contact strip 42 on the base 38. The disk 36 is shown as electrically connected with the secondary 27 of the transformer 26 midway between the ends of the 'i windings ot said secondary, as by wire 43,

and the disk 37 is shown as connected with a wire 44 the opposite ends ot' which are connected with one end of the pri-v mary 25 of the transforn'ier 26A as represented at 45 and its opposite end to one end otl the coil 34. The opposite end of the coil 34 connects by a wire 46 with the contact 42, the wire 46 connecting with one end of a resistance coil 47, the opposite end of which is connected with the line wire 24 through the medium of the wire 48.

The apparatus is shown as includinfr a condenser represented at 49 which is pre erably of the so-called variable type to compensate for different conditions of electrostatic capacity, as hereinafter explained, this condenser being shown as interposed in a wire 50 connecting one of the electrodes of the tube 11 with the disk 37.

The parts of the electrostatic relay nor-L mally occupy the positions represented, wherein the disk 3'7 is out of contact With the contact 42, and the function of this relay, in the particular arrangement shown, is to short-circuit the holding coil 34 in the event ot the approach ot' an object to within a ln'edetermined distance of the elements traversed 'by the high potential current, by the movement of the disk 37 into engagement with the contact 42.

In thenormal operation of they apparatus shown so long as no object approaches any i. l

the electrostatic relay. Thismay -vbe comot the elements along which the highv` potential current travels, the electrostatic re- :v y

that both sides of the high potential circuit lay remains inactive, assuming that the cur-: rent is balanced at both sides of the high potential` current, but as soon .as an object approaches any ot such elements to within a certain distance thereof, an electrostatic field will be caused to beproduced. across the gap between the disks 36 and 37 producing a movement of the disk 37 into engagement with the contact 42, thereby shortcircuiting the coil 34, the circuit thus established being from the wire 24 through wire 43, coil 47, wire 46, Contact 42, disk 37, arm 40, wire 44 and wire 23, it being understood from the drawings that the circuit-supplying current to the coil 34, in the normal operation of the apparatus, is from wire 24 through wire 48, coil 47, coil 34, wire 44, terminal 45 and wire 23.

Upon the approach of an obj ect to any one of the elements traversed by the high potential current, such object takes an electrostatic chargc, which causes current to How through the wire 23, which is substantially grounded in View of the light insulation maintained between the generator at the power house and the earth, the Wire 44, arm

40, disk 37, across the gap between this disk y and the disk 36, to the latter, wire 43 to secondary 27, thence to the element carrying the high potential current and adjacent to which said object extends and through said object to the ground,l the current traversing the wires 29 or 30 depending on the position of the rotating arcs 16 or 17. The operation ot' the electrostatic relay is dependent on the passage of a predetermined amount of current through the relay. It is preferred that the relay operate as stated, upon the passage therethrough of a relatively small amount of current, as for example one-millionth of an ampere, though this may be varied as desired, it being understood that upon operating the relay as stated the switch device 33, by reason of the weakening of the coil 34, will automatically move to open condition and break the supply circuit comprising the line wires 23 and 24.

Itwill be understood that a relay operated by such a small amount of currentl as not to be sensed by a living object may be provided and thus the slightest discomtort to a living object maybe prevented. v

y l-t often happens in the installation of high potentialapparatus that the proximity or" objects or parts of the structure to the elements over which the current flows to the tube, is suchvthat one side of the high potential circuit is delivering an electric discharge unbalanced as compared with the other side 1 thereoiu ln other wordsthe Wire 21, or Wire 22 maybe delivering an electric discharge ,through such object, which would serve to produce Aan unbalanced condition in pensated `for in any desired way in order be in balance, the means provided in. Fig. 1

.being the condenser 49 hereinbefore referred cordance w1 beingl'a condition? commonlywere adjacent the wire 21, existing, as for example,fby reason of the proximity of an object stationary relative to this side of the Vhigh potential circuit and capableof taking'an electric charge.,` It will be `"understood ythat if the electric dischar e to be com ensated connecting theseeonda' y"5B-"betWeen the ends of 'it's 'win dingsfwith1 t, e 'prin'ary n52 ng indicated 'at 54. vr*ffl-11e 'secondary-,53de fc' nectedfby a wire 55 Witlitheianode"terminal 56 of the tube=representeq y Y randbytthe wires '58 andf`59fwithth`e terminalstGOiof The ymani-line Vsupplying wires, correnecteabyefwiie 714 'withtheaislevv the resistance corresponding with the fresist 'ance coil "47, at' Y1. f* fTh" ends of the 'seconf dary `67riai-e1connectedwiththeiends o'f the primary oftheftranjsiformer"flhy Ithe Wires f2 and 73,'fthe sendaryf being' icon"- o "fan electrostatic 4relay suc The Contact 420i theslf fvir'el 75 .lwqith one end 'offvh holdin" and one end of the?"resistance'colflj lfThe `The`iiirent for supplyin the heating cu'itf'ofv the tubeiis supplied t roughthewires 63' and 64 byl the connection'ther'ewith of `the wires? 8 and 7 9 "connecting with the-primary 70 which is represented 'at 82.' They primary f 'o'fa *transformer 81,"fthe "secondary of and secondary areseparatedby heavy insulation dia rammatically represented-'at 83. The vwire 519 'isf Ashown `as providc'ad2 `with 'a switch device 84 'and thewire',l 78 'with a 'curi supplycurrent, 'in accordance with common practice, the voltage being reduced to about f'lhe wire 74 being in el'ect connected with the' '5 'secondary i 153; fthe functioning "of the electrostatic. la 35 nf Fig; aifsthe saine'i'as that'vfin'li'g. script-ion" of its operatie' nebessary: -1 f' f 'Thel @provision f 'PPeefStO-tb 111iiokf the step-down transfornierivloperates tov prodiica unbaltential circuit-between the" cathode the secondary p53, which'fis showni t'oh'ebalanced by Jthe provisin'. 'of-f' the "cndense'rv 49," i

11i. In."

Referring partcula? Ito `the arrangement 'shown' in 3i, the: l-rt'y tf'ube"l illustrated lsf f-z the direct current;'htcatldettype 'represented w90 and 9.1i, a reltifierf repre-- m Smets"` being-represented@e935 94', 195y "andes and its rotating arcs, crriedlb the rotating l disk v9T, at 98gl and 99.1 Thecontact" 94 is eonnect'ed with 'the terminare? by Ythewre ,125

100,1"the'contactt96' li's'fcon'nected with the terminal 89by a Wire 101,:'t`he contact-95 is .connected 'by 'a wire 102`wit`li one' 4end loi? the secondaryilOS offa heavyinsulati'on tra`nsformer ytheprimary of whichfi's repre- 39 75 Vrentv regulator 85; The' 'urpose' of the translformerl '81 'is to st'e'pl own Athe currentto relatively low voltage as comparedwit-h the 90 Aanu therefore"'aepaiiedffdeino causing suchi "current to sented at 105 and the heavy insulation thereu themends; of the prlniary of at 106; and by a wire '107 secondary .103.'

the contact 93 y is Connected with the other' end of the The transformer 104, as

well as the corresponding transformer of Fig.,j,4 is ofthe center-grounded type as explained of the transformer 51 of Fig. f2, its

centerlgwire being represented at ,108, which,k

connects wi h the prlmary 105 by a wire 1083. This arrangement also involves the provision of a transformer 109 corre'spt'md-l lng to,l and ,fnnctioning the same as,A the transformenf=66 of Fic. 2 its secondarv be-,

ing represented, at 110 and connected with 105 by the wires 111 and 112, its primary at 113 and the heavy insulation therebetween at 114, the ends of the primaryf ;113,being connected with the wires 90 and 91, the wire 91 having interposed therein switches 115 and 115 corresponding with the switches 69 and 69, the holding coil for the switch 69 being represented at 116 and the resistance coil, corresponding to the coil 47, at 117. The electrostatic relay 35 has its disk 36 connected bya wire 118 with the wire 112, and its disk 37 with the terminal 87, by a wire 119, and with the holding coil 116 by the wire 120. l In this arrangement the means for supply.- ing low-tension current to the cathode-heating filament of the tube involves the wires 121 and 122 connected with the line wires 90 and" 91, respectively, and with the ends of the primary 123 having the secondary 124 which is heavily insulated from the primary 123 by the insulation diagrammatically illustrated at 125, the wire 122, containing a current-regulating device 126 and beingl grounded through the wire 127. The transformer of which the primary 123 is a part, is al mere insulating transformer, its secondary 124 being connected with the primary 126- of a step-down transformer, throu h the medium of the wires 127 and 128, tle secondary of this step-down .trans- :former being represented .at 129 and the heavy insulation therebetween being represented diagrammatically at 130. The ends pof the secondary are connected with lthe terminal 88 of the tube. The wire 108` connects with the primary 126.

The relav 35 tfunctions in the same manner as ex lained of the relay 35 in Fig..1, and detailed description of the operation thereof appears to be unnecessary y As will be understood by those skilled in the art there is produced an electric field across the space between the primary and lsecondary 126 and 129 respectively which induces a current which flows between the primary and secondary, over the wire'lOl to the contact 96 and through one or the other of the arcs 98 and 99 to the contacts 93 or 95,1depending upon the position of the arcs, thence to the primary 103, wire 108 and back to theprimary 126, but by reason of the arrangement shown this, cur# rent thus derived and which may be of fairly lsubstantial amount, is not caused to trav erse the relay 35 thereby vrendering unnecessary the balancing of the same through the relay, and this arrangement is especially desirable where currents of relatively large magnitude are set up in the apparatus. The arrangement shown presupposes the existence of such conditions as would cause an unbalanced condition in the relay, if not compensated for, the arrangement shown being based upon an electric discharge through the side of the high potential circuit between the cathode end of the tube and the vsecondary 103, as for example by reason of the permanent location of an object sufiiciently close to this side of the high potential circuit as to create such electric discharge by reason of the electrostatic ca.- pacity of the object, and to correct this, a condenser represented at 132 and correspending with the condenser 49 is interposed in the wire 119. .v

l,The arrangement shown in Fig. 4 is identical with lthat shown in Fig. 3 except that means for compensating the unbalanced effect in the high potential circuit created by the existence of the transformer of which the primary -126 is a part, and to this end a wire 133 connects the wire 108 with the contact 94' and hasinterposed therein a condenser represented at 134 of a capacity sufficient to balance the current set up between the primary 126 and secondary 129. The condenser 132 in this case would be provided for the same purpose asthe condenser 132 of Fi 3, viz, to compensate for any condition whlch would otherwise produce an unbalanced eil'ect on the relay 35.

While I have shown certain electrical arrangements embodying my invention, I do not wish to beunderstood as intending to limit it thereto as the same may be variously modified and altered without departing from the spirit of my invention, it being my intention to` claim' myV invention as fully and completely as the prior state ofthe art will pmlt. A l I 'y What I claim as new and desire to secure by Letters Patent, is:

1. Electrical `apparatus comprising, in combination, ahigh potential circuit, a low potential circuit for energizing said first named circuit, apair of plates in spaced relation each connected to said high potential circuit and one thereof movable toward the other when the circuit is unbalanced elec- 2. Electrical apparatus comprising, in potential circuit adjacentfo'ne end of the combination, a high potential circuit, a secondary, means whereby said plates may transformer having its secondary included remain spaced when the circuit on each side in said circuit, a low potential current supthereof is in electrostatic vbalance and may 15Y B ply means connected to the primary of said have the space reduced when said balance is transformer, electrically operated. current disturbed by approach of an object to arresting means adapted to break the low change the capacity of said first named cirpotential circuit, an electrostatic device comcuit, a contact in said space, and means conprising two plates, a connection from one necting said contact and one of said plates 20 10 plate to the middle of said secondary and with said current arresting means.

the second plate connected to said 'high MONTFORD MORRISON. 

